The prior art discloses several alternatives for packaging bulk products, particularly for small particle contents such as rice and grain or powder form contents such as sugar, flour or grain powder. For example, multiwall bags may comprise an outer, lacquer-coated paper layer or wall with flexographic printing on the surface, and an inner layer or wall constructed with kraft paper. Although these prior art multiwall paper bags can be durable in structure, the printing quality is poor and thus not appealing to today's consumers. They are also associated with undesirable contamination of the bag contents with contaminants such as paper dust.
Alternatively, prior art multilayered plastic bags may comprise printed matter on top of a single layer, or a top layer with reverse printed matter laminated to a middle layer so the printed matter is situated in between the first and middle layers. Also a base layer can be laminated to come in direct contact with the inner contents of the bag. These prior art multi-layered plastic bags may further include printed matter, such as graphics, product information, logos, and the like wherein the printed matter is reverse printed to the laminated side of a first layer so that it is viewed through a second opposing laminate layer. While the printing quality of these prior art multi-layered plastic bags can be superior to other known multiwall bags, prior art multi-layered plastic bags are often less durable in structure.
To overcome some of the deficiencies with paper multiwall bags and plastic multi-layered bags, prior art bags for bulk products have also comprised polymer woven bags. These prior art woven bags may comprise a single polymer woven layer with printed matter on top or a top layer of film with reverse printed matter laminated to the polymer woven layer, or alternatively, a top layer of printed paper coated then laminated to the polymer woven layer.
Although the durability of the structure is enhanced in these prior art woven bags, thus making them more suitable for bulk packaging, many common problems are nevertheless associated with these prior art woven bags, particularly where a polymer woven layer is in direct contact with the bag contents. For example, substandard materials and construction can be associated with the fabrication of the polymer woven layer, which often leads to deterioration of the strength and integrity of the bag, and in some instances, mixing of woven strips with the contents of the bag—a significant public health concern.
These prior art composite bags, while functional, nevertheless fail to meet expectations (particularly for packaging bulk products of small particle contents such as rice and grain or powder form contents such as sugar, flour or grain powder), partly because these prior art bags can be aesthetically unattractive as a result of limited printing methods and poor printing quality. Moreover, while some prior art, multi-layered plastic bags have enhanced printing quality and aesthetic appearance, many of these bags are less durable and less appropriate for packaging bulk products. These prior art bags are also associated with undesirable contamination of the bag contents.
Additionally, the oxygen transmission rate and moisture, humidity or water vapor transmission rate of a bag must also be considered when the bag contents comprise dry powder form contents such as sugars, flours, and grain powders. When bag contents comprise dry powder form contents such as sugars, flours, and grain powders, the contents quickly gain or lose moisture until they are at equilibrium with the environmental relative humidity, and may consequently succumb to undesirable affects, such as becoming soggy or clumping together. Bags containing such contents should include a high barrier layer to block moisture and oxygen transmission in the bag.
Prior art composite bags for small particle contents, such as rice and grain products often include poor ventilation which can increase the moisture or relative humidity of the bag contents and the oxygen concentrations in the bag, thus leaving the contents more susceptible to mold formation and spoilage. Therefore, with respect to bags containing small particle contents such as rice and grains, there is a need for a composite bag that provides a plurality of holes that properly maintains the oxygen transmission rate and moisture or humidity transmission rates of the bag contents.